I think my biggest 'wow moment' thus far was yesterday when I used my n810 for a little while. I'd been relatively disappointed with my typing speed on the n900 because of the new layout, which had kept me from noticing how great the keyboard really was- the 810 (which I always loved) felt terrible in comparison. A little more practice on the 900 will probably have me even faster than I was on the larger keyboard.
I've been pretty impressed with the new one thus far. Vncviewer works well (though I need to get rid of the toolbar in fullscreen mode), rdesktop works fine, openssh is openssh...I'm quite happy with Conversations/haze (though I've missed file transfer).
SIP seems to work well with Gizmo but my work asterisk account is acting up (probably something on my end; I'll have a look at that when I get a chance).
I've been scrambling around trying to figure out how to set up bluetooth NAP, but I haven't been able to find much useful information. Finally ran across some promising pages from a gentoo user last night, so hopefully I'll work it out shortly.
I'm looking forward to getting dialcentral/TheOneRing working, but using the GV page is OK for now.